The association between dental status and temporomandibular osseous changes: a morphological study on Roman–Byzantine skeletons

The aim of this study was to evaluate the association between dental status and the prevalence and severity of osseous changes in the temporomandibular joints of human skulls from the Roman–Byzantine period. Fifty‐eight skulls from 36 men and 22 women between the ages of 19 and 63 years were studied, and the following parameters were evaluated: morphological osseous changes in the articular surface of the condyles, tooth wear and molar support. A significant correlation between age and dental wear or loss of molar support was observed, although no correlation was noted between age and morphological osseous changes in the condyles. The loss of molar support was significantly correlated with morphological osseous changes of the condyles, whereas no significant correlation was found between dental wear and condylar changes. This study demonstrates that the loss of molar support can serve as a predictor of osseous changes in the condyle. Reduced molar support may be one of the aetiologies associated with morphological osseous changes in temporomandibular joints. Further studies should to be performed to investigate this potential correlation.     

Relationship between frontal craniofacial morphology and horizontal balance of lip‐closing forces during lip pursing

The objectives of this study were to quantitatively evaluate the relationship between frontal craniofacial morphology and the horizontal balance of the lip‐closing forces (LCF) generated during maximum voluntary pursing‐like movements in patients with mandibular deviation. Thirty‐one subjects (median age 25·4 ± 8·9 years) without a history of orthodontic treatment were randomly selected from among the orthodontic patients who visited our hospital. Lip‐closing forces was recorded in eight directions during maximum voluntary pursing‐like lip‐closing movements. The subjects were divided into the deviation (two males and 11 females) and non‐deviation groups (four males and 14 females). There was no significant difference in the total LCF between the deviation and non‐deviation groups. In the deviation group, the mean LCF value on the deviation side of the upper lip was significantly lower than that detected on the non‐deviation side of the upper lip, while the mean LCF value for the deviation side of the lower lip was significantly higher than that for the non‐deviation side of the lower lip. In contrast, no significant difference in upper or lower lip LCF was detected between the deviation and non‐deviation sides in the non‐deviation group. The difference in the LCF generated in the lower lip between the deviation and non‐deviation sides was significantly positively correlated with mandibular menton deviation and significantly negatively correlated with the difference in maxillary height between the deviation and non‐deviation sides. These results suggest that the horizontal balance of the upper and lower lip LCF produced during pursing‐like lip‐closing movements in patients with mandibular deviation is related to frontal craniofacial morphology.     

Forensic age estimation based on magnetic resonance imaging of third molars: converting 2D staging into 3D staging

Background: Established methods to stage development of third molars for forensic age estimation are based on the evaluation of radiographs, which show a 2D projection. It has not been investigated whether these methods require any adjustments in order to apply them to stage third molars on magnetic resonance imaging (MRI), which shows 3D information.

Aim: To prospectively study root stage assessment of third molars in age estimation using 3 Tesla MRI and to compare this with panoramic radiographs, in order to provide considerations for converting 2D staging into 3D staging and to determine the decisive root.

Subjects and methods: All third molars were evaluated in 52 healthy participants aged 14–26 years using MRI in three planes. Three staging methods were investigated by two observers. In sixteen of the participants, MRI findings were compared with findings on panoramic radiographs.

Results: Decisive roots were palatal in upper third molars and distal in lower third molars. Fifty-seven per cent of upper third molars were not assessable on the radiograph, while 96.9% were on MRI. Upper third molars were more difficult to evaluate on radiographs than on MRI (p?p?=?.375). Inter- and intra-observer agreement for evaluation was higher in MRI than in radiographs. In both imaging techniques lower third molars showed greater inter- and intra-observer agreement compared to upper third molars. MR images in the sagittal plane proved to be essential for staging.

Conclusion: In age estimation, 3T MRI of third molars could be valuable. Some considerations are, however, necessary to transfer known staging methods to this 3D technique.     

牙冠延长术应用于磨牙缺损修复的临床评价

目的:比较两种不同治疗方法修复磨牙缺损的临床效果。方法:选取86例缺损位于龈下的患牙,分别采用牙冠延长术和牙龈切除术暴露断面,修复后6个月观察临床疗效。结果:牙冠延长组总有效率明显高于牙龈切除组,差异有统计学意义。结论:牙冠延长术能有效恢复患牙生物学宽度,是磨牙缺损的最佳选择。     

复方氯己定含漱液预防干槽症临床观察

目的:评价复方氯己定含漱液预防下颌阻生智齿拔除术后干槽症的临床效果。方法:临床搜集需拔除下颌阻生智齿的342例患者,共342颗牙,随机分为复方氯己定含漱液组(A组)、口服抗生素组(B组)和消炎抗菌可溶止血纱布组(C组),比较3组术后干槽症的发病率。结果:A组干槽症发病率显著低于C组(P<0.05);A组与B组、B组与C组间比较,干槽症发病率均无显著性差异(均P>0.05)。结论:下颌阻生智齿拔除后,口腔应用复方氯己定含漱液可有效预防术后干槽症的发生。     

Severe trismus due to bilateral elongated mandibular coronoid process in an infantile-onset Pompe disease patient: A case report

Pompe disease is a rare neuromuscular disorder characterized by orofacial muscle weakness with consequent dysphagia and poor weight gain. We report the first case of severe trismus due to abnormal elongation of the coronoid process of the mandible in a child with infantile-onset Pompe disease. Bilaterally elongated mandibular coronoid processes cause abnormal impingement between the coronoid process and the zygomatic process, which in this patient, resulted in a maximal interincisal opening of only 6 mm. Although rare, clinicians should be aware of the development of coronoid process elongation in neuromuscular disorders with hypotonia, specifically those involving hypotonic orofacial muscles.     

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??Objective??To study the influence of the inlay on the stress of the remained tooth tissue??three-dimensional finite element is used to analyse stress distributions of the tooth endured different MOD inlay restore at different remaining buccal wall thickness. Methods??Using ANSYS Workbench 15.0 software to established 3d finite element model of mandibular first molar restored by all-ceramic inlay restoration with designed MOD cavities. Analyzing the influences of different remaining buccal wall thickness to the stress distribution and tendency of the teeth. Results??Different remaining buccal wall thickness of the tooth tissue on the stress level had a certain influence??the lowest stress level was the remaining buccal wall thickness of 2 mm. The stress level of occlusal coverage restoration was higher than inlay restoration. Conclusion??The study found that different remaining buccal wall thickness of the tooth tissue on the stress level have a certain influence??try to keep healthy dentine??avoid enamel without foundation is effective means of inlay restoration reducing the risk of tooth fracture. Remaining more tooth tissue is not suggested to restore occlusal coverage.